U.S. Pat. Nos. 4,060,074, 4,086,918, 4,114,607 and 4,114,608 of Chesebrough Pond's Inc. disclose inhalation devices which provide simple, safe, inexpensive means for inducing a patient to expand his or her lungs and exercise his or her respiratory musculature. These devices include one or more see-through chambers having a light weight article in each chamber, and means, such as flexible tubing and a mouthpiece, to allow a person to withdraw air from the device and to cause the articles therein to rise when the predetermined inhalation effort is achieved. In doing so, the rise and fall of the light weight articles provides the user with an incentive to exercise his or her respiratory system.
When the user exhales air from his or her lungs, however, such air can flow into the inhalation device via the mouthpiece and flexible tubing. This exhaled air contains higher levels of carbon dioxide and normally is ladened with water vapor. Upon repeated inhalation and exhalation the amount of carbon dioxide inspired increases while the amount of oxygen decreases. This effect is not desirable. At the same time the water vapor of the exhaled air can cause condensation within the chambers of the inhalation device. This condensation is undesirable because it may contain detrimental bacteria which may be inspired back into the lungs of the user, and because it clouds and obstructs the view of the light weight articles within the chambers.
Although these problems may be obviated by instructing the user to remove his or her mouth from the device upon exhalation, with weak, feeble or very ill patients, that may be more difficult than would appear. These users often are somewhat uncoordinated and disoriented and may not be fully able to follow such instructions.
It is the object of the invention, therefore, to prevent exhaled air from flowing into the inhalation device without requiring the user to remove his or her mouth from the mouthpiece.
It is another object of this invention to provide a dual valve for an inhalation device which freely permits air to be withdrawn from the device upon inhalation while preventing the flow of air into the device upon exhalation.
Additional objects and advantages will be set forth in part hereinafter and in part will be obvious herefrom or may be learned with the practice of the invention, the same being realized and obtained by means of this dual valve recited in the appended claims.